1. Technical Field
The present invention relates generally to seat cushions, and more particularly, to a seat cushion adapted to relieve pressure of ischial tuberosities of a user.
2. Related Art
Seat cushions have been shaped and molded in a variety of ways to relieve pressure on users. In one example pressure-relief technique, pillars are employed throughout a cushion to relieve pressure. However, these devices are not adequately anatomically focused and therefore relieve pressure indiscriminately. To address this shortcoming, some devices provide different depth pillars for different regions of the body. However, these devices are relatively unfocused anatomically. In addition, these devices are expensive to manufacture because of the number of pillars required, many of which are unnecessary. The multiple pillar devices are also not optimal for all users. For example, a lighter user may not find the same comfort in a cushion designed for a heavier user.
Cushions that are generically contoured to a user""s form have also found acceptance. These devices, however, do not provide adequate cushioning for interior areas of the body comprised of bony prominences. One interior area of the body that requires pressure relief to prevent reduced blood flow is the ischial tuberosity area of a user. The need for this type pressure relief extends to all types of seat cushions including vehicle seats, chairs, wheelchairs and so on.
In view of the foregoing, a need remains for seat cushion that does not suffer from the problems of the related art.
A seat cushion including a first and second pillar positioned specifically for receiving the ischial tuberosities of a user is provided. The pillars relieve the pressure of the ischial tuberosity areas, but are easy and inexpensive to manufacture. In addition, the position of the pillars can be customized for a particular user. Hence, pressure reduction is accomplished only where it is needed. In addition, the seat cushion provides focused pressure relief that is beneficial to those user""s with less fleshy padding on their ischial tuberosities, but does not penalize those with extensive fleshy padding because they largely compress the cushion without engaging the pillars. In one embodiment, graduated slots are provided to create the pillars. The slots provide a transition from the greater pressure relief of the pillar to the lesser pressure relief of the intact cushioning member. The invention can be used on flat cushions and on cushions with a molded shape.
A first aspect of the invention includes a cushion consisting of: a cushioning member having a first pillar positioned for receiving a first ischial tuberosity of a user and a second pillar positioned for receiving a second ischial tuberosity of the user.
A second aspect of the invention is directed to a cushion consisting of: a cushioning member made of a foam; a first pillar positioned in the cushioning member for receiving a first ischial tuberosity of a user; and a second pillar positioned in the cushioning member for receiving a second ischial tuberosity of the user, wherein each pillar is formed from cuts formed in the foam that gradually recede to zero depth.
A third aspect of the invention provides a seat cushion comprising: a substantially planar cushioning member made of a polyurethane foam, the cushioning member including only: a first pillar formed in the cushioning member for receiving a first ischial tuberosity of a user, the first pillar having a polygonal cross-section and a graduated slot extending from each corner of the polygonal cross-section; and a second pillar positioned for receiving a second ischial tuberosity of the user, the second pillar having a polygonal cross-section and a graduated slot extending from each corner of the polygonal cross-section.
The foregoing and other features of the invention will be apparent from the following more particular description of embodiments of the invention.